The only problem with starting out using low plate voltage is that even with tubes that generally tolerate low B+ the distortion performance and overload margin will be vastly different than when operating at higher voltages. It would be fun to try but it seems to be kind of an advanced technique. If going that route I a FB design would I think be more likely to succeed. Maybe plate to grid (or CF to grid) FB circuit using 12AU7 or 6SN7 would be worth a try. I think an open loop design at that low B+ would likely have detectable coloration. Fun to try though. Have considered a car battery powered 12AU7 myself as a fun garage preamp project.
Something like this
Something like this
